Diesel Injectors

This waveform is taken from a Vauxhall 1.9 Z19DTH. This uses Bosch EDC15C common-rail direct injection. The injectors use the common electromagnetic solenoid type actuators. The control unit limits the maximum current to 20amps. The control unit contains capacitors that provide the high voltage used to operate the injectors, usually 2 capacitors for a 4 cylinder engine.

Bosch solenoid Injector current and voltage (EDC15C)

This image shows the same type of Bosch solenoid injector as above, only I have included the independent voltage signals per channel. I have also included a ‘maths’ channel to show the differential voltage equivalent. This sample was captured from a 2000 Peugeot 2.0 with Bosch EDC15C.

Bosch solenoid Injector voltage and current with ‘maths’ channel (EDC15C)

The following waveform is taken from 2011 Peugeot 1.6 9HR engine. This uses Siemens-Continental SID 807 engine management. The injectors use Piezo electric actuators. The specs on this type of system suggest a maximum of + – 10 amps current and up to 140 volts. The control unit contains capacitors that provide the high voltage used to operate the injectors, usually 2 capacitors for a 4 cylinder engine. I don’t know why the current is so jagged as yet and so need to test further. There was no recorded fault with this injector, but there was a fault with one of the other injectors. It may just be a sampling rate issue!

Siemens-Continental Piezo Injector current and voltage (SID 807)

This waveform is taken from a Peugeot 2.0 RHR using Seimens SID 803A. This also uses Piezo electric actuator injectors, as above, but you can see the current is much smoother than in the previous capture. This is a more common sample in my experience, but it may just be an evolution of technology issue.

Siemens Piezo Injector current (SID 803A)

I captured this sample to show the voltage on both sides of the injector measured against a common ground. This is from a Siemens-Continental SID 206 system, fitted to a 2008 Ford 1.8 KKDB. You can see why sampling the voltage across the injector, gives a cleaner signal.

Siemens-Continental Piezo injector voltage and current (SID 206)

The following sample is from a VW Audi (VAG) 2.0L PD engine. This is a Bosch solenoid unit injector. It is driven by the camshaft, which generates the high pressure and controlled by the ECM. This is not a high voltage system.